Tuft gripping strength test method and apparatus for carpet primary backing mats

A test method for measuring yarn and tuft or loop gripping strength characteristics and capability of tufted nonwoven primary backing mats for making tufted carpets, the tufted primary backing mat having no additional binder or adhesive on the backside of the mat prior to making tufted carpet is disclosed. The test apparatus and test method can be used for quality control purposes and for evaluation of experimental or new candidates for primary backing mats for making interim tufted products for carpets that are more resistant to tuft or loop defects. Revealed is a new and critical Quality Knee characteristic of primary backing mats that is crucial for minimizing tuft or loop defects during the tufting process and also the force magnitude on the yarn necessary to pop the tuft completely out of the primary backing mat sample.